The present invention relates to aerosol valve assemblies to dispense products from pressurized aerosol containers, and more particularly relates to easy-to-open valve assemblies for dispensing viscous and semi-viscous products from such containers including compartmentalized containers.
In a conventional form of aerosol valve assembly, a vertically acting aerosol valve is opened to release product in the aerosol container by downwardly depressing an actuator attached to the top of the upstanding stem of the aerosol valve body. When the actuator is released, the valve is closed by a metal spring acting upwardly against the valve body. The valve stem has an upwardly extending discharge passage, a groove extending about the stem periphery, a lateral valve orifice (one or more) extending through the stem wall into the groove, and a stem-encircling sealing gasket for fitting into the groove and closing the lateral orifice except when the valve is actuated to depress the stem lateral orifice below the gasket.
There are a number of recognized disadvantages to using the conventional metal spring. The spring has a significant upward force, requiring a significant downward force by the user to open and maintain open the aerosol valve. Further, the metal spring provides well-known corrosion problems in the presence of certain products dispensed from aerosol containers. In addition, the metal spring adds significant cost to the aerosol valve assembly and requires a separate assembly operation. Despite all of these disadvantages, the metal return springs continue to be used in the vast majority of aerosol valve assemblies because a sufficiently satisfactory alternative has not been found.
In certain instances, resilient plastic members have been adopted to replace the metal spring, the plastic springs being separate from or integral with the valve housing and/or valve body of the aerosol valve assembly. Such plastic springs avoid corrosion, but can be difficult and expensive to mold, require a significant user force to open and maintain open the aerosol valve, and may be more subject to failure than metal springs. Representative prior art for such plastic springs is found in U.S. Pat. Nos. 3,675,832 (Ruscitti); 4,471,893 (Knickerbocker); 4,477,001 (Galia); 5,895,029 (LaCout); and German Offenlegungsschrift 2128981 (1971).
Various attempts have been made to eliminate valve return springs, whether metal or plastic, but such attempts have been inadequate and/or overly complicated in concept and construction. One such attempt is shown in U.S. Pat. No. 3,982,674 (Mildern) wherein upon valve opening, fluid or powder (i.e., essentially non-viscous) products flow up a dip tub to and up a central stem of the aerosol valve. Propellant acts against a diaphragm or a piston portion of the valve housing, in combination with low pressure in a chamber directly above the piston portion and the stem gasket flex in its groove, to close the valve after actuation. U.S. Pat. No. 4,211,347 (Mildern) is somewhat similar but requires dual sealing gaskets. U.S. Pat. No. 3,610,481 (Marraffino) requires two sealing gaskets in a co-dispenser and notes that where the two gaskets are relatively thin flat gaskets, a compression spring may additionally be needed to close the valve. U.S. Pat. No. 3,257,035 (Jones) illustrates a valve configuration with a dip tube, wherein a gasket sits in a groove but does not close a valve orifice into the stem. The gasket is said to tend to return, but may not return, an actuated valve stem to its non-actuated position, in a container system where product discharge continues through the valve stem until the container is empty regardless of the return of the stem to its non-actuated position. This latter patent accordingly does not require a return spring, but only a means to keep the valve closed until its initial actuation, and the valve is not easy to open because of the frictional engagement of a valve stem and surrounding sleeve.
It is further known to dispense viscous aerosol products from containers, such products including shaving gels, hair gels, bath and shower gels, and body lotion gels. The viscosity of such gels may range from 10,000 CPS (centipoise) to 50,000 CPS (centipoise) at room temperature, for example. Semi-viscous products such as hair mousses and whipped cream are also dispensed from aerosol containers. Such viscous gel products are generally not dispensed through dip tubes on the aerosol valve assemblies, and generally are dispensed from compartmentalized containers, wherein the propellant is in one compartment and the product to be dispensed is in a separate compartment. One common configuration of such compartmentalized containers has a movable piston in the aerosol can, with propellant below the piston and product above the piston with access to the aerosol valve. As product is dispensed from the aerosol valve, the propellant forces the piston upwardly to maintain pressure on the product. A second common configuration of such compartmentalized containers utilizes a collapsible, flexible bag attached to the aerosol valve housing or the can bead where the mounting cup is attached. The bag has access to the aerosol valve and contains the product to be dispensed. When the aerosol valve is actuated, propellant in the compartment between the bag and container inner wall acts to collapse the bag compartment and force product out the aerosol valve.
Semi-viscous products such as hair mousses and whipped cream likewise are not generally dispensed through dip tubes on the aerosol valve assemblies, and are generally dispensed from single compartment containers.
The present invention is intended to provide an easy-to-open aerosol valve assembly, characterized by the absence of a return spring, to dispense viscous products such as gels and semi-viscous products such as hair mousses and whipped cream from aerosol containers. The aerosol valve assembly is retained within a mounting cup, and includes a valve housing and a vertically-acting valve body with an upstanding stem. The stem has a central discharge passage, a groove extending into and encircling the outer wall of the stem, and one or more valve orifices extending through the stem wall in communication with the stem discharge passage and the stem groove. A single elastomeric gasket is captured between the valve housing and the mounting cup, has a central opening, and encircles and extends into the stem groove to seal the one or more stem valve orifices when the valve assembly is not actuated. The valve housing has a side wall encircling the valve body, and a bottom wall with both a central opening and a plurality of product delivery openings spaced outwardly from the bottom wall central opening. The valve body in turn has a lower portion which may be hollow and which extends downwardly through the valve housing bottom wall central opening to center and stabilize the vertical valve in the valve assembly. The valve body further has an intermediate outwardly extending portion positioned below the valve stem which overlies the valve housing bottom wall with its product delivery openings.
The product flow in the present invention extends upwardly from the valve housing bottom wall product delivery openings to a product passage between the valve housing side wall and the valve body, which passage extends upwardly to the at least one stem valve orifice and the stem discharge opening when the valve assembly is actuated. When the valve assembly is actuated, the portion of the gasket surrounding the gasket central opening is pushed downward by the stem groove so that the at least one stem valve orifice is no longer sealed. The gasket cannot completely escape the stem groove upon valve actuation, however, due to a stroke-limiting surface on the valve body that engages the valve housing upon a predetermined distance of downward movement of the valve body. The gasket portion of the gasket surrounding the gasket central opening accordingly remains partially within the stem groove upon actuation of the valve.
When actuation of the aerosol valve ceases, the valve is fully returned to its non-actuated, closed position by virtue of several important features of the present invention. First, the flexible single gasket when bent downward during actuation as previously described, acts to bias the top of the stem groove, and accordingly the stem and valve body, back to closed position wherein the gasket returns to its essentially non-flexed or flat position sealing the one or more stem orifices. Second, the viscous or semi-viscous product flows through the valve housing bottom wall product delivery openings, and acts upwardly against the valve body intermediate portion overlying the bottom wall. This in turn also biases the valve body upwardly. Third, the pressure of the viscous or semi-viscous product, acting upwardly on the valve body lower portion extending down through the valve housing bottom wall central opening, further biases the valve body upwardly. Fourth, the viscous or semi-viscous product flowing through the product passage between the valve housing side wall and the valve body exerts a considerable frictional force on the side wall of the valve body to bias the valve body upward. These various aspects of the present invention act together to assure a reliable closure of the aerosol valve assembly while eliminating any metal or plastic return spring. The absence of a return spring allows the valve assembly of the present invention to be opened and maintained open with considerably less user force. The latter is a desirable and perceived advantage to the consumer. In addition, there is none of the corrosion and other problems associated with metal and plastic return springs.
The design of the present invention is unique, simple and economical to manufacture and assemble. There are few parts, and the bottom wall of the valve housing may be sloped downwardly and inwardly so that the lower part of the valve body is easily guided into the central opening of the valve housing bottom wall upon assembly.
The present invention has particular applicability to viscous gel products dispensed from the afore-described compartmentalized container, but also may be used in single compartment containers with semi-viscous products. In neither case are product-carrying dip tubes required or used with the present invention.
Other features and advantages of the present invention will be apparent from the following description, drawings and claims.